<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script type="text/javascript">
			var c=()=>{
				let w = document.documentElement.clientWidth //获取设备宽度
				let n = (20*(w/320)>40?40+'px': (20*(w/320)+'px'))
				document.documentElement.style.fontSize=n
			}
			window.addEventListener('load',c)
			window.addEventListener('resize',c)
		</script>
	</head>
	<body>
		<div class="">
			555
		</div>
	</body>
</html>
